Normal-Insulator-Superconductor (NIS) tunnel junctions are solid-state devices capable of cooling thin film or bulk payloads at sub-Kelvin temperatures. The performance of NIS refrigerators has improved steadily in recent years and we will leverage this progress to build an array of microwave polarimeters with integrated NIS cooling. The use of NIS refrigerators will improve pixel sensitivity, size, and mechanical robustness. By design, the polarimeter array will be well matched to a future suborbital mission to study polarization in the cosmic microwave background. The array will also demonstrate the suitability of NIS refrigerators for a future NASA satellite mission.